Well packer



E. L. POTTS WELL PACKER A ril 28, 1959 5 Sheets-Sheet 2 Filed Nov. 4, 1955 frne: 2 Z. Poi/s INVENTOR.

'A ril' 28, 1959 5 Sheets-Sheet 3 Filed N v. 4, 1955 INVENTOR.

ATTOR/Vf) United States Patent WELL PACKER Ernest L. Potts, Houston, Tex., assignor to Cicero C. Brown, Houston, Tex.

Application November 4, 1955, Serial No. 545,015

1 Claim. (Cl. 166-121) This invention relates to well packers and particularly to packing structures of the type employing a resilient and pliable packing element which is actuated by fluid pressure to effect and maintain a seal with the wall of a confining enclosure such as a well casing.

The present invention is also directed to packer structures in which the packing element is combined with a ring of anchor elements or toothed pipe-gripping slips which surround and embrace the resilient packing element so as to be expanded into wall-gripping engagement with the surrounding pipe by expansion of the packing element in order to anchor the packer structure to the surrounding pipe.

Such packing structures, therefore, necessarily include combinations of resilient non-metallic sealing elements and metallic support and anchor elements. When subjected to high fluid pressures particularly for extended periods of time, the pliable material comprising the packing element will often be extruded or otherwise forced through the spaces between the metallic support and anchor elements and the enclosing element with resultant destruction of the sealing element and its sealing function.

Accordingly, it is a primary object of this invention to provide an improved packer structure of the pressure seal type wherein the destructive extrusion of the packing element between the support elements of the packer structure and the surrounding casing is substantially obviated.

An important object is to provide an improved packer structure including a resilient packing element of the hollow pressure-sealed type and a metal support ring composed of a plurality of segments encircling the body of the packing element to be radially expandible by the expansion of the packing element, the segments being provided with overlapping circumferentially slidable portions adapted to close the spaces formed between the segments by expansion of the packing element to thereby substantially obviate extrusion of the packing element through such spaces.

A further object is to provide a packer structure of the kind described wherein the segments forming the support ring comprise toothed pipe-gripping elements which when moved outwardly by expansion of the packing element serve to anchor the packer structure to the surrounding well casing.

Other and more specific objects and advantages of this invention will become more readily apparent from the following detailed description when read in conjunction with the accompanying drawing which illustrates one useful embodiment in accordance with this invention.

In the drawings:

Fig. 1 is an elevational view of a differential-pressure typeof well packer employing at opposite ends thereof two packer structures in accordance with the present invention and shown positioned in a well casing;

Fig. 2 is a longitudinal quarter-sectional view of one of the packer structures included in the well packer of Fig. 1, the packer elements being shown in retracted or inactive positions;

Fig. 3 is a cross-section taken generally along line 3-3 of Fig. 2;

Fig. 4 is a fragmentary internal perspective view of the support and anchor elements of the packer structure,

the parts being in the positions illustrated in Figs. 2 and 3;

Fig. 6 is a cross-section taken generally along line 6--6 of Fig. 5; and

Fig. 7 is a View similar to Fig. 4 showing the positions of the support and anchor elements in their expanded or active positions.

In the drawing, Fig. 1 illustrates a differential pressuretype well packer installed in a well casing C and employing a pair of packer units in accordance with the present invention and designated generally by the numerals 10 10, secured to the opopsite ends of a tubular body 11. A mandrel 12, slidable through the registering bores of the packer units 10-10 and body 11, is employed to function as a sleeve valve to open and close the bore of the packer structure whereby, in the presence of pressure fluid in the casing, to create a differential pressure across the packer structure in order to actuate the same.

Differential pressure packers of the general type described are disclosed in C. C. Brown US. application Serial No. 389,512, filed November 2, 1953, now Patent No. 2,829,717, and Serial No. 403,328, filed January 11, 1954. It will be understood that the present invention is directed not to the well packer as a whole, but to the packer unit 10 which may be employed in well packers of the kind described, or in other types of well packers, and in other well tools requiring annular sealing units.

Packer unit 10, shown in greater detail in Figs. 2, 3 and 4, includes a tubular packing element 15 constructed of flexible resilient material, such as natural rubber or one of the artificial rubbers, and having an axial bore 150. One end 15a of packing element 15, which end will be referred to as the outer end, is of generally outwardly flaring cup-shaped form adapted to engage the wall of the enclosing casing C. The outer end portion 15a of the packing element may be tapered to form the relatively thin annular lip 16, which, when subjected to internal fluid pressure will be urged outwardly in tight sealing engagement with wall C (Fig. 5). The inner end portion 15b of the packing element may be of substantially cylindrically straight form and is secured at its inner end to a metallic base or support collar 17. Collar 17 is reduced in external diameter at the end contiguous to end portion 15b to form a neck portion 18 provided with an annular recess 19 in its outer periphery and defining an upwardly facing annular shoulder 20 at the upper end of collar 17. The upper end of neck 18 forms an upwardly facing flat annular surface 21.

A ring R, composed of a plurality of complementary generally rectangular segments 22, closely encircles and embraces portion 15B of the packing element adjacent or contiguous to collar 17 The end portions of the segments 22 contiguous to collar 17 are provided with transverse inwardly projecting upper and lower ribs 23 and 24, respectively, which are spaced apart so that the lower rib 24 seats snugly in recess 19, being radially slidable on shoulder 20, and upper rib 23 extending slidably over endsurface 21 of neck 18. Ribs 23 and 24 thus cooperate with recess 19, shoulder 20 and surface 21 to form radiallly slidable connection means between the segments and the support collar. The rib spacing and dimensions are made such, with relation to the cooperating portions of the collar, as to provide close clearances between the engaged portions of these elements.

It will be understood that in the contracted position of packing element 15, segments 22 will form a substantially continuous ring, the side edges of the adjacent segments being in close abutting relation, as best seen in Figs. 1, 3 and 4. It will also be evident that as packing element 15 is radially expanded under internal fluid pressure, segments 22 will be urged radially outwardly'into'en'gagement with the inner wall of easing C. Segments 22 may be provided on their outer faces with teeth 25 which are adapted to grip the wall and thereby anchor the packer structure to the casing when the packing element has been expanded.

When the segments 22 are radially expanded in response to the expansion of packing element 15, the spaces, indicated by the numerals 26, between the adjacent side edges of contiguous segments are necessarily expanded circumferentially (Figs. 6 and 7). Under the fluid pressures to which the packing element will be subjected in operation, these spaces will provide relatively wide gaps through which material composing the packing element may be extruded or forced by the pressure on the packing element. In accordance with the present invention, means are provided by which these gaps or spaces will be kept closed at all stages of movement of the segments to prevent extrusion therethrough of the packing material. The means employed for this purpose comprise flanges 27 which extend along one side of each segment throughout its length and projects generally laterally or circumferentially into overlapping relation to the next adjacent segment, the flanges 27 being shaped to conform to the shape of the segments and to extend into close sliding relation to the inner face of the next adjacent segment, so as to minimize the space between the flange and the segment which it overlies. The flange on one segment and the portion of the adjacent segment overlain thereby provide mutually overlapping portions of suflicient width, circumferentially considered, to maintain the overlapping relation throughout the full range of expansion of the ring.

Each flange 27 may be also provided with a lip portion 28 turned at an angle to the plane of the flange in order to extend over the outer ends of the adjacent segments to thereby close or cover the outer end of space 26 between these segments. The opposite end of each flange 27 extends to a point substantially flush with the inner face of rib 23, so as to be in close sliding engagement with end surface 21.

As shown in the illustrative embodiment, flanges 27 comprise metal plates which are shaped as described above, to conform to the internal shape of the segments and may be secured along one side edge to the inner face of one segment in any suitable manner as by means of welding 29. It will be understood, however, that flanges 27 may be cast or formed in any suitable and conventional manner as an integral part of the segments. Moreover, it will be understood that the flanges may be on the exteriors of the segments instead of inside as illustrated.

In the illustrative embodiment, packing element 15 is secured to collar 17, segments 22 and flanges 27 by molding or vulcanizing the packing element directly to these metallic elements, this being a well-known and common expedient in this art. The functioning of the structure will not be aflfected by such direct connection. It will be understood, however, that instead of thus securing the packing element directly to the segments and flanges, the latter may be held in close embrace about portion 15b of the packing element by other conventional means, such as the well-known garter springs (not shown). Any arrangement by which the segments may be held in close encircling embrace about portion 15b will be satisfactory, provided it enables the segments to be radially expanded and contracted by the expansion and contraction of packing element 15.

With the structural arrangement described, it will be evident that by closing the spaces between the ring segments by the mutually overlapping construction as described and by providing the close radially slidable connections between the ring segments and support collar 17, also as previously described, no crevices will be produced by expansion of the packing and anchor elements which will be of suflicient size to permit extrusion of the plastic material composing packing element 15, even under high fluid pressures maintained over extended periods of time.

By employing the externally toothed segments a combination packing and anchoring structure is provided which is fully self-supporting under fluid pressure and provides a compact, highly eflicient packing structure.

It will be understood also that where this type of anchor is not essential, the ring of segments 22 may be smooth surfaced and will form an articulated expandible retainer or ferrule adapted to effectively support the packing element and obviate extrusion thereof through or past the support elements under fluid pressure.

In the illustrative embodiment, support collar 17 is provided with an internally threaded socket 30 in which an end of body 11 may be threadably received to compress an annular packing 31 seated in a recess 32 formed in the wall of collar 17. Mandrel 12 is provided with an externally enlarged section 33 forming a sleeve valve which, when moved axially through the bore of the packer structure, will engage and radially compress packing 32 and thereby close-off bore 15c through the packer structure in order to establish a diflerential pressure across the packer when fluid is present in the casing. Body 11 may be provided with a conventional double ended Jslot 34 which cooperates with a J-lug 35 projecting from mandrel 12 to limit the extent of movement of the mandrel through the well packer structure in opening and closing the bore thereof. 1;,

The mode of operation of the packer unit will be evident from the foregoing and should require no further explanation.

It will be understood that various changes and mod; fications may be made in the details of the illustrative embodiment within the scope of the appended claim but without departing from the spirit of this invention.

What I claim and desire to secure by Letters Patentis;

A packing structure including a non-metallic cup,- shaped packing having an annular lip about its open end adapted to engage the wall of a confining enclosure, said packing having an axial bore, collar means secured to the opposite end of the packing, a ring composed of a plurality of complementary segments having toothed outer faces encircling and embracing the body of said packing contiguous said collar means and radially expandible by expansion of said packing, longitudinally spaced upper and lower inwardly projecting transverse ribs on the end portions of said segments adjacent said collar means, an outwardly projecting annular lipme nher on the collar means receivable in close sliding engagement between said ribs, vertically extending flange means rigidly mounted on the inner faces of each of said segments extending in over-lapping circumferentially slidable relation to the adjacent segment whereby to close the longitudinal spaces produced between said segments by expansion of said packing to thereby prevent extrusion of said packing through said spaces, the ends of said flange means remote from said collar means having out wardly turned lip portions extending over the ends of said segments and the spaces therebetween, the opposite ends of said flange means extending over the upper one of said transverse ribs and the spaces therebetween into close sliding relation with the adjacent end face of said lip on the collar means, said packing being molded directly to said collar means, said segments and said flange means.

References Cited in the file of this patent UNITED STATES PATENTS Conrad June 19, 1956 

